1. Technical Field
The present invention relates to a conductive roll, a cleaning roll, a cleaning unit, a process cartridge, and an image-forming apparatus.
2. Related Art
Cleaning units having a cleaning blade made of an elastic material such as rubber, in which, for removal of developers, such as toner, adhered to the surface of a image-holding member such as a photoreceptor, one edge of the blade is brought into contact with the surface of the image-holding member have been known in the art as cleaning apparatuses for image-forming apparatuses such as electrophotographic copying machine.
Such a cleaning apparatus is advantageous in that the configuration thereof is simple, low-cost, and the toner can be removed efficiently. It is very important in such a system to bring the contact area of the cleaning blade into contact with the surface of an image-holding member stably, and with uniform pressure, over a long period of time.
Generally, an external additive that is a substance with a smaller particle diameter (average particle diameter: approximately 1 nanometer or more and 50 nanometer or less) than a toner is mixed with the toner to improve the powder flowability, charging properties, transfer efficiency, and the cleaning efficiency of the toner. Because the blending amount of the external additive depends on the specific surface area of the toner, the blending amount of the external additive increases with decreasing toner particle diameter. Naturally, as the consumption amount of the toner during image formation increases, the amount of the external additive reaching the cleaning unit also increases. For example, due to the large number of photographic originals, the amount of toner consumed is approximately 10 times greater in a full-color image-forming apparatus, in which development using four color toners is sequentially performed, as compared with toner consumption in common apparatuses for black and white document and thus, the amount of the external additive used is also increased significantly.